Question

Упростите выражение:
а) (2x-5)(3x+4)
б) (x-3y)(2y-5x)
в) a(a-5)-(a-2)(a-3)
г) (2n+1)(4n^2-2n+1)

Answer 1

$tt(2x-5)(3x+4)=6x^2+8x-15x-20=boxed{6x^2-7x-20}\\(x-3y)(2y-5x)=2xy-5x^2-6y^2+15xy=boxed{17xy-5x^2-6y^2}\\a(a-5)-(a-2)(a-3)=a^2-5a-(a^2-3a-2a+6)=a^2-5a-a^2+5a-6=\boxed{-6}\\\ttboxed{a^3+b^3=(a+b)(a^2-ab+b^2)}\\(2n+1)(4n^2-2n+1)=boxed{8n^3+1}$

Answer 2

а) (2x-5)(3x+4)=6х²-15х+8х-20=6х²-7х-20

б) (x-3y)(2y-5x)=2ху-6у²-5х²+15ху=-5х²-6у²+17ху

в) a(a-5)-(a-2)(a-3)=а²-5а-(а²-2а-3a+6)=а²-5а-а²+2а+3a-6=-6

г) (2n+1)(4n^2-2n+1)=8n³+4n²-4n²-2n+2n+1=8n³+1